Summary of findings 4. Inhaled tobramycin (28 days) compared with inhaled tobramycin (56 days).
| Inhaled tobramycin (28 days) compared with inhaled tobramycin (56 days) for eradicating Pseudomonas aeruginosa in people with cystic fibrosis | ||||||
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Patient or population: adults and children with cystic fibrosis and a positive microbiological isolate of P aeruginosa from a respiratory tract specimen Settings: outpatients Intervention: inhaled tobramycin (28 days) Comparison: inhaled tobramycin (56 days) | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Inhaled tobramycin (56 days) | Inhaled tobramycin (28 days) | |||||
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Eradication of P aeruginosa from the respiratory tract: time to next isolation of P aeruginosa from BAL, sputum or oropharyngeal cultures Follow‐up: 27 months |
By 26.12 months, 50% of people in the 56 day group can expect to have experienced a recurrence of P aeruginosa. | By 25.18 months, 50% of people in the 28 day group can expect to have experienced a recurrence of P aeruginosa. | HR 0.81 (95% CI 0.37 to 1.76) | 651 (1 RCT) |
⊕⊕⊝⊝ low2,3 | |
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FEV₁: % predicted Follow‐up: 27 months |
There were no major short‐ or long‐term changes in spirometric parameters were observed during the study period. | NR | up to 881 (1 RCT) | ⊕⊝⊝⊝ very low2,3,4 | Changes in lung function were not reported separately for each treatment arm. | |
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FVC: % predicted Follow‐up: 27 months |
There were no major short‐ or long‐term changes in spirometric parameters were observed during the study period. | NR | up to 881 (1 RCT) | ⊕⊝⊝⊝ very low2,3,4 | Changes in lung function were not reported separately for each treatment arm. | |
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Growth and nutritional status: weight, height and BMI Follow‐up: 27 months |
No significant differences in weight, height or body mass index were reported. | NR | up to 881 (1 RCT) | ⊕⊝⊝⊝ very low2,3,4 | Numerical data were not reported or comparative results across the treatment groups. | |
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Frequency of infective pulmonary exacerbations: number of exacerbations per patient year Follow‐up: 27 months |
47 per 1000 | 9 per 1000 (0 to 188 per 1000) |
OR 0.19 (95% CI 0.01 to 4.00) | 771 (1 RCT) | ⊕⊝⊝⊝ very low2,3,5 | |
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Isolation of other micro‐organisms from the respiratory tract: number of positive cultures per patient year Follow‐up: 27 months |
There were no consistent trends reported in the isolation of non‐P aeruginosa organisms (one isolate only of Stenotrophomonas maltophilia which was seen in the 28‐day arm). | NR | up to 881 (1 RCT) | ⊕⊝⊝⊝ very low2,3,4 | Numerical data were not reported or comparative results across the treatment groups. | |
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Adverse effects to antibiotics Follow‐up: up to 27 months |
There were no significant differences between treatment groups in terms of any reported adverse events at any time point. | NA | up to 771 (1 RCT) | ⊕⊝⊝⊝ very low2,3,6 | ||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). BAL: bronchial lavage CI: confidence interval; FEV₁: forced expiratory volume in one second; FVC: forced vital capacity; HR: hazard ratio; NA: not applicable; NR: not reported OR: odds ratio; P aeruginosa: Pseudomonas aeruginosa; RCT: randomised controlled trial. | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
1. In the included trial, 88 participants were randomised but not all participants contributed to all outcomes (unclear how many participants contributed to some outcomes).
2. Downgraded once due to risk of bias; methodological information was limited and unclear in the included study and there were concerns of bias due to selective reporting of results and lack of blinding.
3. Downgraded once due to applicability: the included studies recruited only children; results are not applicable to adults.
4. Downgraded once due to imprecision: no numerical comparative results available.
5. Downgraded once due to imprecision: very wide confidence intervals around the effect size
6. Downgraded once due to imprecision: some wide confidence intervals around effects sizes (small event rates) and a lot of adverse events analysed increasing the statistical chance of a spurious finding.